Forget about the 2 pieces of chocolate cake, what's done is done! Try to now work out how you are going to overcome this emotional eating issue for next time...you obviously know that a fight with hubby/family is the cause, now you just need to work on what to do to avoid comfort eating. Take some time to write yourself a list of things you can do (when you are calmer) so that when it (or something similar happens) you can go to your list and do something from there instead of stuffing your face and then feeling terrible afterwards....trust me it works and it is worth it to write some "distractions" down that don't involve eating!
sorry for the long winded explanation!
I hope whatever the fight was about with your loved ones will soon be resolved.